SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4627e6e58b4846930f76172a064041e8dcdbc363ccc13fd9e97619382cf512b1' 
  AND token = 'hzAETglUBFnet5c6kpD1ltt+qoDpaWYiWHJuWKDbwAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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