SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c4fc335f89e18bd2126994c05ef0475a35f47a6469182c3d5f5f78e923897d2' 
  AND token = 'nQA2u+9jSa0oKn4MNZZwvT67yD6NeUgCRqJwKjBMFo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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