SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48dbf309ee7727d28e0da445fd0d0e2dde68d255aa212aaa5ae8328f17e841d7' 
  AND token = 'xmWHj0xEhrYabp3FUpyFBPJpKOBrgFopwz1DUVLj7lg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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