SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '20e9e082698b3348ebb6c9d0ecbe871a90ee6c42cde6fb83e4dc5ef7eae4fa72' 
  AND token = 'V04R9Kx6IyE/RXLTtHrGoiT03fVda1vQgjLagvjTdxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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