SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e00db304fb86e68698fc18b4749cb789ec340eea6123d820618214713fd63d0' 
  AND token = 'btAFm1rbj3gBu1TfpQKS6It8oRJXodEV3Lxgz3QAB7M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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