SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c135509662d5a75f9702d2bf6a87fe9b2fef57438e7fd4d7123be6bc41701d23' 
  AND token = '9C4pJyIQTGod2XgejPV8m+cpNdCPVF5ZBU2QDLc9Q3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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