SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82909a4edd813162fd39e52d0d8c37707b5bd1915bf579c25fbc957e90d018ca' 
  AND token = 'nlhkR4IK2eH5B3OaKhbWxtCc98NdtyhM1ffeQGUil9g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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