SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48f3f92ed482310d0e15b5b3ec57f42f800978f0d02329e7da490039592009f0' 
  AND token = 'hdtmSxsMdI2erSKcYh0HnXOfANOCwe7mSgCHC/tE1bU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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