SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '806681e03d8b0cc23aa55c82d926801fd338b18013339010a8efd4fd72182d50' 
  AND token = 'p5dUsGr9MBlGSiIDGOnN59qdQAn1HqWzqWYQtJmXj04=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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