SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ea1952129c2496684e8781105e08bf43b87e06dc7dd6bedd9c28fa44f99b0e64' 
  AND token = 'FLl4ZmlN6EdIyZcqg/cGJ0Q8AYRA+54YYBwk0NUCfCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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