SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d0873d4252667658f689a27b788fd2e91cde492740222ff8fbb94abfe195867' 
  AND token = 'UuihaObA60dKQcheQIflOL1OG/joE4IcnusiawdTnl4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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