SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87f5808f713fa6d5fc283857bb1fe7002d0d2356e11698340ee2fa0baa196382' 
  AND token = 'pJoDwf5GCdR1fNSQMUMT2rpUmiBkNXCW8nAr3QqnBSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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