SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0eae25e3e033fe938aa855d74307befe822e121a0ead7f2995de7d5bd8f5b71' 
  AND token = 'a3gOyaBUIhLpzghkZmhrQ7ZNJ45DMA6285Rlk/vyTZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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