SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91e0f57a7a90a8d454a24c31a869cc4ded52cb73af51d8dd292ad7584d72f854' 
  AND token = 'mxW12Ic/KOa+aTvIZNTk+7RQTWJGrXxNrlvHXfvju3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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