SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c79401a8a59116d63f06fa008f9308ad813de08d51543c3bfd3a248b0b81de4a' 
  AND token = 'mA1YmlsI5NteDdTsdWRUdgXzparoxFkC0dUbtW9eaQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}