SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ad2a61149dc53c0f914a9d18ae56b37506d2a254bc10205849fd689cb3cb952' 
  AND token = 'tuRTU7C8w7+N6YbqzxEnVjWVCLwjQ9FnGdkh4iPPg78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00073

JSON explain

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