SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bbbb10bea8225fccf94ddd19101ab1b0ebaeff41e74b034fd004b1bcf0090c3' 
  AND token = 'C4eLHEKC5uRjsALtTAtKKQ1l/HFnOY0MYAkDVdMi6hI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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