SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bb4cd8a25096baaf36162e5d27ab8010e69c49659691d3978c5ff0960a556ad' 
  AND token = 'suuBvf52dvYvTIV2jIjDI0mDOQxRTcFhxLPBOvrP858=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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