SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cec052cfdc8253e8673399887fb2303d425ddda4bf2fd32e000ba1376c6f1fae' 
  AND token = 's97j3V3Kpo2fh2OL3rZb90CoxpUhiKubltQWejL7HrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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