SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6648b6fef4a82d559db6d463a20c9b15408a7e00c45e8c3f3eaaa78a17b21d7a' 
  AND token = 'TJjgyF+qXqM6/ULu1F0b0csb3Y+RfCW5pZlmvmfnZIs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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