SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d29d2c3fca11045535e746122a14febcdc36ff23207649100eed028290829df' 
  AND token = 'njQeIixDemUxysOrwWocg1j0xMztPsWN94WZDqHzCuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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