SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8cb4391dc5cd2525fa27f9754d6de4dde3bf6277a406c90d14cd9d14346f749' 
  AND token = 'YrEIlT5Z5fTTBVxuQWbEl2d3PRig1mTk//W/Qk42MUk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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