SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4618099ac82e61fb31806fed6cb1cb49e1750f31956e5dfbded54272b19a525' 
  AND token = 'f7psiwyhX9dpgvKHilPSLX1Bzo2NOAFlXWxFJp8JTrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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