SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '853643689d9c23f1db93a70d7bd56805a6d9cdf8ccd1817a22a15280bb5203fa' 
  AND token = '6P2Pz/JCGbVoClHWSDmNBqWvKD/nwIhFxkbWYUUmuo4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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