SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d09fd8c09d663909ee89c07cf0cbb755c54d90d9278f2c2bf6fff8e24d6bf62' 
  AND token = '19HXvrsgV+stc1XNNHZrb4pPIqpgeADN0FTDcmhqGEI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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