SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cad1e80f9d3aa78ea5307640f2cd09d311357ee2787dbd372ed2a9c38caca6f3' 
  AND token = 'SfyftiaHF0OrNSgn58fuFGBAkr3xuuJBi4lV2ziLRIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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