SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '202ac6069369282e05c3378943d9e6c858af816c139df162d78bfb7a7ef7ab98' 
  AND token = '5cS4vQUxZVADmdBZ/HzfmaXwEddIFdz+BVHYzudJ+Ks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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