SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5de36a55d9150e7333073777c650d6e2739f2a5d43bd4ec7d8a123921a92833c' 
  AND token = 'lwIKfnK4PmnIxobnxHhwFmc5lEQ6bm3qTxJjxtYiIUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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