SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43c78745a47b2d06bf3668779059e710b50b51721211d7c4d5eeedf93787cf3d' 
  AND token = 'JEUL99Oj3yPIpmFoZAt1RRnVmqMOzkDmkuS+GiXt0LI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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