SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdf4ac5983e1b90b7927345006ea88784e6e0aa2178debe4c041c6d7f743506d' 
  AND token = '03ZXlTMOuIe4toLYnhe/arQVbkVPyfAWgUDHyqKOBGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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