SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c53b2f8f34442fc5145d4115602ec935e888a033641416c489496dc61e830947' 
  AND token = 'AX31nrsUFVVL4J7w51pMbBaqnrGlfARBaUD7ZD35H9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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