SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57c0bca6c328553c5c4ddf39244dbaefed4403ab9243d576ec046ec84fb2e08a' 
  AND token = 'OdZWV6CUb176ohvEFnx88zTjaojVXkCieeF1TxXqJnE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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