SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7157d9cbcdf4a5f3b0cbd9f50a2201ff18a575deebee291c6ba75e66000a75ad' 
  AND token = 'CmcIpltLBLHrPSld257C9qYe5rJBb5VUePzSPTZd4s8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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