SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b392bc1156337604a22e55b2c2ec7b79f6c54116289f5597b17eacb040abc03' 
  AND token = 'j9ULI/qD7HY33pHoChpcaqnAs7cKZrd9GL+JYyvXJDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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