SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b91ee24e2de9847c82616ed3e20222e004bdc20753dcf35f0677a62fcf36866' 
  AND token = 'h4BCAjIskrgoRYUuShXvG768TmCDZYUsHfD0Wf3S9eo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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