SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '928c52d0eef7ec1839dabee0d1b92eefe31428f7756829672bc0eaf0745af36a' 
  AND token = 'J0MlywLx3EE/qokzLCeuKq1u0igx3P1Ag2r9tT4vacw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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