SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17a3ef70c5785428f588ba8fe1d404d5a913542a0c2e418937ce548cdd478688' 
  AND token = 'bAtLzRspJxghtBa1NTnEpdGylVwFBtVpiLk1qM/wO1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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