SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d8c89533239e43aee01264ac04b639d979981f06f16832f03279a35ea984c1e' 
  AND token = 'xH0P2sjFqN1JmZvG5q3MhtlNHlHYti/6qJaToZcD7qo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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