SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b340adc9528c39c1240f2a0fbcc6e30aaab3dbe299dc49d4b6368476fcd4f67' 
  AND token = 'XZ1LWJ6WBJEgz2My/Sa/GPftNKdv9q7+PWQgKFSVJ0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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