SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdf473ee6014583143357da521e00180d2b47f522048bbbaafdafd368d126896' 
  AND token = 'PhZsaIvq7pDFu5Q6vL3GkuvZZrdxTtfdqGBYuo5c7Pc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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