SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46455299e563e64fefeb2442d4d287ea5dd1d70fc8e18e961415c31edae9cb54' 
  AND token = 'NL+pIjR4GE7srntKp3xI1SsbRcIMrhxuFisTIqFz/ds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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