SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee5d0a76695ce0c3ba6ee2bcb06bb6aaccbff16c50d910103632cdd4b8782e43' 
  AND token = 'JSCwDq57uVC3DYXYBRdS3AKZkbi0Pk1Fjiv6Q5nkAo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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