SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '659aca70da65f4662f381cfae3b6decd21cef344b4c7499943f407caab50e720' 
  AND token = 'V6NDqTRrBFX+/FK8wh5WJKr+CQUEk7JoGj1rr/lvsQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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