SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f450284d68509781da73d9024a57e077c2b1aa227d067a794de2bc7938102aa' 
  AND token = '4N/T6tt4QQUZVt6h+EE4oZ26Z1ybPyqm91xcNQZq4Q0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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