SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56bd4cfa226116acf2e4a230d7a62fd38a24ffdd648bef1ca82f89bae14a937b' 
  AND token = 'i6xf5gNy9o7JZht7mjGHlJo87lXf00W2v5z0++iiBKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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