SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6d10d51f33065417993887d7cd438bf3aedebcf085a3f2676763f877b6428255' 
  AND token = 'WK6FrvNl9RcLA2M3bdjiNYfbgQF91BusOwEmCxZX6wo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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