SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4a85a3d490a156dad81f2d2017a01c3d7eafdd93ae6b52580cfbe924339f365' 
  AND token = '+URWGB+vQArYZ8EDF6lOnh99Ps5gPznlsEfrYQYJIb8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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