SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2bff48685a7c7db2075253cbd05a50e7b80856d0fa2691fca98fa3e7c6e5c43' 
  AND token = 'v/7k6MtgytvzGPL6L1QM1YNcXjCTvc7S2TXSAvlIsvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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