SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c457f2a6c819bb7553e12507174e4dd6b7b7fddc48b3b4c0687e988a3a6649bc' 
  AND token = '87pV14lPgRKGt0chvkaBb1UuXAZphjCuW6DRbM0Mh1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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