SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e61b07697fc7b90fa1a03d32c53b15fbee0c2f9d398c734fa3b6dcd78d0d3a67' 
  AND token = 'yJpmASmhwWTVZBNegmybpPX3JeWRblGIQ9vh1MwCmXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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