SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed308595d2e7e9f76f2d4f56cc1d694cd0c07c5fb263bc2a5eda00349cc59eb9' 
  AND token = 'r+vFZt9dLmNohNzWvlhPgEGKBBj0VR4MSnXKWECwDjg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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