SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '661c4fc0c0af5102c05cf54bf18880ed11c8019637cd766039d4af65e661042b' 
  AND token = 'xDySRDA06S6LUhdgWQDpQVvApL823Jghdhw2ATvYzQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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