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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efdd37f29cbe41d611622d7721e3ae2365e5b97b7dc35169bb1317a8ee24a6c3' 
  AND token = 'BtTm2nthFkc+z8a4A//3mzCZ0V+CiYELn6veU5vZ/Ic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}