SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b58338fcd18759576e74a66ab2d706ec4e1c8fa3ac58e89192beb465cfe6e51' 
  AND token = '1sL2litkCCr8pL1ze5zOKzRWkYQEd56Gvr584v8E5jY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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