SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '708d7d6f1db4f5fc3fe7ba9760b95e0e945f85654cc8f2ef2cddd2150f9d932e' 
  AND token = '7mRNwN4v5GGFw0UDm4oHiAiJQogysstTrrWn2ZwYn80=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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