SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52f3f92740e77c24484be374c16cf9385bc3e78f25519f8525568a9661f547eb' 
  AND token = 'g2tjb81JYKNVia7giDIjwifK2ymh6LX6/tZnYXMJlJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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