SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '31f1f94ff07be29d954ce988cac3489e24fdd512fc0650aa7c32900e985e1aa2' 
  AND token = 'so/Pdo3V7Fu+Gwz/fACk+qFBB/CR5hh9VYBWXf/n/Qw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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