SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b4ba11ce06f3cac0fb85c6a38cc3aba2f135c63655c863a061d87efd5b1ff5b' 
  AND token = '7tYVkYZAWPlqnzDvTk/qjFSfqRdw8Cc//gjfVGox4ZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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