SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf8a0e1f1b381aba3223db47980da6ec074fd5aaed93eef57e99946a3a0de948' 
  AND token = '9OEyQc+H6m8v034izcugQlPb0J+lDlV0iiBfKxmzufA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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