SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '289ce8f54941c3a2f470accf87757c28dfd7ed2ea6eff68df7fe83295869c0a1' 
  AND token = 'B6NU//e2O3GzjG5dnG2AzD5ZcwrNUV5Wp4gOsLi1uwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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