SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f288d8ba6390846d9ac44e41c1aa152927943a67401fcb18e4c3651b73beb675' 
  AND token = 'TNu78+hN8GlYupJue99uLOCLUwaVDrIwhdS7mFuqOyY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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