SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e81e484df8d52d2859e87856ef352cb36e2c838624f94cea425a7cb44cbc8fc7' 
  AND token = '4gXRjF4wdS7aTGTW/689ElqKmEZRGW0lnX178SLpPSw=' 
  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"
    }
  }
}