SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d67345f04a654cebbb619cac34649b0cd6afd21c6a3a56edbd99b7690703254' 
  AND token = 'NXzx7lz3JOZDY2G8tKwPdsDQOmVETFu9Tgdks+BJsfs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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