SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92235ae4ce93cb52deccef0ed2fe6e3cc914e1926764c1f50cb1360c5c5101a4' 
  AND token = 'TNrS3m7+s6uDKbY/ONRd8WWG8QvCvBvEp5Umiv+Yp8Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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