SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c873442b0053f514acaf927f933529997a43113d6984418e8f162c8c1f7158d0' 
  AND token = 'qGRJPG3PHQIBKudW0PKxpuYof/Q8xvMfjEGZxIMpuVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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