SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e5c372c07fbe5d583e83eded9947af38baedb9e9e1c169736323d68680a347f' 
  AND token = 'SRdWp+Q0tLzf4y2YV2wYaMF1U3h2WLTYzXW+KHVyT24=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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