SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f91625519d548ab042b8f0b38dbc65ab5f4016fbb35b79ed0d0841e8d6ced83' 
  AND token = 'uSU5ILcyRcTd3KzuO/WQN1ZZs8Nfa2Nlob6h3qHKNZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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