SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2391ac19c09ad3ac8bce421dbbae467eff24658f79f5e1d1d4920579d7838236' 
  AND token = '+mN2AjvXrWXE2sfWuaztj01o5LXFC/pawJDWBeSrSKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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