SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '542f3b9fb65bf3ed1dec7cf5a4db2ba895d8a4316b64d3a9ba204a28062f651f' 
  AND token = '7wmThuFr9FCdJCA98pQhSpX5HfFjYR5dnNKOjO+UWz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}