SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5dddd7adb87fc5343fea20a4606bdf1e6ad0d4611310380da35edc8f24140009' 
  AND token = 'MRmPnjExe9gFnc9H/Qqba/k7aBIzdyeKkXHcHCRK/Kg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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