SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7afd39e5318ef8601a8bf4d497389f0318ee9ac9d81993d3113b5224bb5b6182' 
  AND token = 'OazZdiNGOPoiMFD3ADlhLpzMFHRvfGPk/3vSy/NrkNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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