SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76309c7f79431bafaad346a430967e37a728001201a4ddd26dc304ca825bf64d' 
  AND token = 'vSfdGrhcHiJgzRYDS0NF+A419rWBfeq72sob5YhGbUs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00236

JSON explain

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