SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a209185ec76f6ea2842a5a2f3609384185c4bdd9b501a9b4cc5dab6d1402aefd' 
  AND token = 'SU/olgmhA0EdXqp6duZobjk0hKXjz+30sXCcevTS4IQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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