SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aee7b73e744f8a0210093cd2350fa33a5caf39148d358411b021dd9d3750a98b' 
  AND token = 'ubIX9Q+ahmxpSgSqE0LRGSYgqGaek5IUoOQDmDm4ZAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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