SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '879bea7ced98f413e545e2b92789acc3d4ae9527742ec75028476eeec97acf17' 
  AND token = 'iJv2LgYGVO4PYvHOF8KcGRDBfgrs05CszjpdaiqgdrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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