SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afd72bb9133f4652eeedf4f575f56c7d368362b92ff4ee37d8400bf25bc4541d' 
  AND token = 'fLMuqgJYsKRpH6DFKvyuZplBzn7iW7FFxNinQmQ7KK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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