SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5578938e77d67024c6729b455f0a7a96846982824273f44470d1415d5992f1c6' 
  AND token = 'IC8itSqfKCSqQCzmLhvm/MyBU7qQ/Hj8TAnnC/BBq/c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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