SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7799f54b6c427dec685bf38dd28e721133911a33ad73c3fc9d0bcfbd4d244893' 
  AND token = '9Hr86Gnf6cJYGu3da8GXI3yfZ/zyaYXGRRjCVuMBT3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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