SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ff9d187f8011ade0fb7a6804b4ec5a62861eba8f00d28eb4e4af468e3bf37ec' 
  AND token = 'F+x9t5VQqQSj83LoKQpA6rwE0kqakmgNuLhm27IsRQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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