SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '796de631c938dfaeb673be7d584cafd6409e3137d52ebf415f90694ad2107fe4' 
  AND token = '+7Se1fylLlK6Gwevqs8kHUng+aOhxGUZhEuEezaIL4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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