SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9ebd9e96e2ac3281b1b56dcd43b0116c34202c81c4e3017a59d4175b9191780' 
  AND token = 'jEFYxrY8IJxGaoRAfMzPRmYaJBk+4Lm7YQ1aD2oUhWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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