SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea6f9aee5e72a654e8701056e6887c87faa7ed164b3121f6075a539bd40fbdd2' 
  AND token = 'DGVq8fNhRa+3oIovqzL60uzui3jXuFOBSFeGJEHYq74=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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