SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '996269a2313844d7b1881a23864dbd00e75874d44ffaab69d81bae99302d4ac2' 
  AND token = 'tVgGe1l3pvuyX6gFkc57M3jsguP37B71crHI4avDE60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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