SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9cc52a71541b5a4b40e69ea8052372fb6eca27c68cb6501dd5825c3b370ba31' 
  AND token = '0hjlZfqum/rJXinwgBgN96LlmBhix+wEj+p5MNV/cm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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