SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b21d0b255c1cda5b1a1ce8e0eec9ca8fea0898247daa8906be729e54bd4ce46' 
  AND token = 'BGEog8crDLtYnp2HW57DK57bar1RDcOSSsjmI3XKvGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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