SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ec2c3b0644c94b37148dacbaacf47f256858b58819fc4748fe99d85db66e1c4' 
  AND token = 'CBMeiePiCGCMvIWSDD2Qn/Zdb643vhF5ZAQexr7Q5TU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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