SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e194e6a8228b0fd93cae27d2c4fb59d8415807016188adc0604fb801e0beaca' 
  AND token = 'oXTxbbCr571wdqUCH1Ug8p1ZMCDrjGKeIPY1h67JaCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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