SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6afaeac5807702118feb23ab84da387711e5235ac03f5ef43e0585426c4e42fb' 
  AND token = '8Wpvk6XAYJD7Cr4DMlzzt2nZBAVCzdzpjAVrtjfgmb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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