SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4c8fd85142113bd294c90bb9ca8f23787cd13d3ddb06058314eeb12810ac651' 
  AND token = '60oammfbkbAZXYVyWgQmm0JBX5cU4khya/pVxD0u+WE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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