SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1c48bec418c4b536ae528bac311954ec4dd7d7fe329e30258e93d5fa615c41f' 
  AND token = 'ZgsJQqDRXSDAlydZlSvTxiBExMoyx/Gg9BXWKp+dOrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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