SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e0b2d52013cde06cee3a167e58dfdbd36ca9e0f0745d7eff15ba2c754baad1d' 
  AND token = 'nAXubsZ3QY7AVlC6XLCBCz9mnRGYH4cSZjkiRsiNN3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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