SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c35c80824854035efdb318027e4185a865da99860a80eef32175167a2a9a1eae' 
  AND token = 'o2E9Bej6EpzFPKqWTfjtZeLiR0Fn2WWYMM3OFLwL2sI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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