SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9b29c090e5f70ac9197b8c76bac05f5e2b0d58f3504a985d23897194435edbc' 
  AND token = '5NtC+h1p3Pq7wzt6lifcZIbeINFVD28kCIlgts7gOLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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