SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '185ec23e37f82e7eddeeabe3aae2f636d6abc720a6f5065bb7f793d9ecff3450' 
  AND token = 'oPEoRpNsPSFHEPiQGToMuKu6aBO4KDUpdDBcjRfxCBI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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