SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56c878a6e56d539475b2b0370a87427815d25bd4c5c8d569c800a49f15344078' 
  AND token = '8enu0YvDHZMW+DssKzDzgHjhKv/eOeqUEZgC18VrOVM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}