SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd5b7e45082061368fb93b3dcd1a9497f1103d5d4899719acd2c68bb78a5db0c' 
  AND token = 'AFbfTEEMj1uSW3F2kf0cTImrufDXb28wwtusXSpclas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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