SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57d87e0572c04a541a964ba48f9bf901cfdeffdd23574a140960ed83d570be5c' 
  AND token = 'yduKCtbOxN31/TM3dQAA3h4trqBRf4d3qSBJd/viIPs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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