SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'be3e8c3c65400a2630f071c1a73856643989b7d17893d46afe8b312eb80487a5' 
  AND token = 'haU6eDE7+VIihmnls5bZplU/TyExeJtvAJ7js6GzEZ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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