SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73d13128f7e8013aa2cf3a4a0c3c8055257cd51e7a5f61a2351f63573c754951' 
  AND token = 'OZPgy3IELPEic/xbyXsgJFE2hIrRAfSR1CuIbhgGzFM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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