SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bcfe557445495752ed9af9d2bfb52242bf454b7fe672cd3f6c59038063dca35' 
  AND token = 'pjZyu94ZPcoFxe2AZ+/mxhbRSYfbqL3cHz9Krjhsq1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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