SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '864bc38a9d98c96ca7d300bb3db25b6dd63fa5d88e1866f3e0a8505be6751564' 
  AND token = 'lf+Cg52SYU5ja1pWEpGqVcfd2k9Lhc1YmzxKYduRlAE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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