SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5644ca23029cec0750b49d779be2408802bfbad6ad39df774a9cd33051acf8fb' 
  AND token = '2MZoo0nL3mRgwtxfdC1KpuThR1X6UVdHTak0Q9t8mZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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