SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5aa85fedcfc11d229f5dbdb5a34dc553cff01fe45eceb6720faaaf9be9070427' 
  AND token = 'ytFTvJYoDEXBfjsa3bsnFUV/B502bnrP0TyDD9tbWRg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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