SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43cf829bb6570f174f1c3a1345bc188ade7f9669ba33800a7cdf6ddb8348ecb6' 
  AND token = 'vgkTTjNAbVWR2CISqH+1RkPqUbkOE2OCIh4y+zHy/vU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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