SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e7641fa6cb22ac7ad6dc8ac131e877bee8581d2f7fbb90398e3e47979c0d8fd3' 
  AND token = 'l6xh9/oWoNNhXIXovg/K15lUrOHjDfWHCJXQZMi/KG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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